The medical school interview feedback forum has a lot of good info on this.
I'm replying because this is probably the one school that I felt asked a lot of "prepared" questions that were meant to pry into interviewees more. My first interviewer was hardcore. He even opened up by asking me what I got on my SAT's...loser. Anyway, they all have prepared questions that they are supposed to ask and a lot of them were situational. For instance:
1. name a situation where you had to go out of your way to help someone.
2. name a situation where you had to deliver bad news to somebody
3. name a situation where someone in a group you were in acted immorally (i.e. how would you react to a classmate cheating?)
This guy at the end of my interview even pulled out a couple of newspaper articles and asked me to react to them. One was about how there was a problem with air-conditioning or something in a prison and how inmates as a result, were suffering from heat exhaustion. Another question he asked (I'm being totally serious) is how I would go about trying to figure out how many gas stations there were in the country (someone also mentioned this question in the UB medical school interview feedback forum...as proof
This was my first interviewer only though. My second one was totally easy - she just sat down, talked about my EC's, my research - overall, she was just very cordial and friendly. Honestly, I think I had two ends of the extreme in terms of my two interviewers there.
I would definitely expect to get some of those situational questions though. I think my first interviewer was probably the toughest guy they had there so don't generalize and think they're all going to be like that. However, if you want to prepare for some of those questions I mentioned above, it definitely wouldn't hurt. All it takes is a few minutes to think of some good examples. Good luck - I thought it was a pretty nice school - although a little too far away for me.